Single ply roofing membranes with multifunctional biodegradable release liner

ABSTRACT

A roofing laminate includes a roofing membrane, preferably a white roofing membrane, which is covered with a protective sheet. The protective sheet is tinted so that it has a coloration distinguishable from the roofing. The roofing laminate is applied to a roof surface and the release liner protects the outer surface of the membrane from scrapes and dirt during installation. Once the roof is installed the protective sheets are removed from all of the membrane sheets, exposing a clean surface.

RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 13/440,415 filed Apr. 5, 2012, said application being herewithexpressly incorporated herein by reference.

BACKGROUND OF THE INVENTION

Membrane roofs are roofs that are covered with a polymeric sheet ormembrane. These polymeric sheets can be, for example, polyvinyl chloride(PVC), thermoplastic olefin (TPO), or ethylene propylene diene monomerrubber (EPDM), as well as many others. The polymeric sheet is positionedover a roof surface and held in place by fasteners, adhesive, orballast. Adjacent sheets are bonded together along lap seams to form aunitary single sheet of the polymer covering the entire roof.

Generally, the roofing membrane is either white or black. Theoretically,the membranes could be basically any color.

One chooses a white membrane roof for either aesthetic purposes or toreduce energy costs by reflecting thermal energy. In either event, it isimportant that the white membrane roof sheeting be clean, i.e., white,subsequent to installation or it will not provide the aestheticappearance desired nor have the same reflective properties.

Particularly, when replacing an existing roof, it is difficult to keepthe new sheeting clean. In a re-roofing application, a section of theold roof covering is removed and new roof membrane is immediatelyinstalled in its place. This allows the roof to be fully covered eachnight. As subsequent sections of the old roof are removed, the rooferswalk on the previously installed new membrane. This can scratch and marthe new membrane. Even when installing a new roof, it is difficult tokeep the white membrane clean during installation.

SUMMARY OF THE INVENTION

The present invention is premised on the realization that duringinstallation of a single-ply roofing membrane, the surface of themembrane can be protected from dirt, scratches and scrapes by providinga removable tinted or colored release liner adhered to the membrane. Therelease liner is left in place during installation of the white membraneroof sheeting and be removed after completion of the installation. Thetinting or coloration on the release liner ensures that the releasesheet is noticeable and not inadvertently left on the roof. Further, therelease liner can be formed from an environmentally degradable polymerso that even if some portions of the release sheet remain on the roof,they will degrade quickly and basically wash off the roof.

The objects and advantages of the present invention will be furtherappreciated in light of the following detailed description and drawingsin which:

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of the present invention;

FIG. 2 is a cross sectional view taken at lines 2-2 of FIG. 1;

FIG. 3 is a cross sectional view of an alternate embodiment of thepresent invention;

FIG. 4 is a perspective view of the present invention duringinstallation;

FIG. 5 is a cross sectional view of an edge portion of the presentinvention during installation and prior to removal of the release sheet;

FIG. 6 is a perspective view of an alternate embodiment of the presentinvention;

FIG. 7 is a cross sectional view broken away taken at line 7-7 of FIG.6.

FIG. 8 is a cross sectional view partially broken away of a secondalternate embodiment of the present invention; and

FIG. 9 is a perspective view of a third alternate embodiment of thepresent invention.

DETAILED DESCRIPTION

The present invention is a roof laminate 10 that includes a roofmembrane 12 and a release sheet or protective sheet 14. The roofmembrane 10 includes a first surface 16 and a second surface 18, and,likewise, the release sheet 14 includes a first surface 20 and a secondsurface 22 which rests on and covers the first surface 16 of membrane12.

Membrane 12 can be formed from any polymer typically used in roofingapplications. These include polyvinyl chloride, thermoplastic olefin,ethylene propylene diene monomer rubber polyethylene polyolefin, as wellas others. The membrane can have a bottom fibrous surface referred to asfleeceback, which improves bond strength in a fully adhered system. Themembrane 12 is preferably white or slightly off-white. It can be anycolor. The present invention is most useful when the membrane is alighter color, such as white or off-white, and is least advantageouswhen the membrane is black. Although theoretically one may want toincorporate a protective covering over a black sheeting for use in thepresent invention.

Membrane 12 can be any typical size. These can be as narrow as 5 feetand as wide as 40 feet. Length can be 50-100 feet or more. Membrane 12has a thickness effective for use in a membrane roof system. Generally,these will be 20 to about 160 mils thick. Roofing membranes are waterinsoluble and designed to withstand environmental conditions for atleast 15 to 20 years.

The protective sheet 14 is a thin polymeric sheet which can be formedfrom a variety of different polymers. Although the protective sheet canbe clear, it is preferable that it be tinted with a color that isdistinguishable from the color of the membrane 12. Thus, if the membrane12 is white, the protective sheet 14 is preferably any color other thanclear or white, such as green, red blue or yellow.

Preferably, the protective sheet 14 is formed from an environmentallydegradable polymer. Exemplary environmentally degradable polymersinclude polyhydroxyalkanoates such as those disclosed in U.S. Pat. No.5,070,122, polylactic acid and copolymers of polylactic acid andethylene carbonmonoxide copolymers as disclosed in U.S. Pat. No.5,135,966. These polymers break down over a period of time, preferablyless than a month when exposed to certain environmental conditions, suchas sunlight, heat or moisture, or a combination of any of these.Preferably, these environmentally degradable membranes will break downin a matter of days.

The roofing laminate 10 is formed by separately forming the roofingmembrane 12 and the protective sheet 14, and laminating the twotogether. If the protective sheet 14 includes an adhesive layer, thiscan be formed by co-extruding a pressure sensitive adhesive along withthe membrane, or subsequently coating the formed membrane with apressure sensitive adhesive, in particular a thermoplastic pressuresensitive adhesive. The protective sheet can also be made naturallyadherent to the membrane by incorporating tackifiers into the protectivesheet and applying the protective sheet to the membrane in a slightlystretched condition which liberates tackifier. The exposed tackifierprovides weak adhesion of the protective sheet to the membrane. Once theprotective sheet 14 is laminated to the membrane, the laminate 10 isformed into a roll 24.

Alternately, as shown in FIG. 3, a thin layer of adhesive 25 may beapplied between the first surface of the membrane 12 and second surfaceof the protective sheet 14 to adhere the two together. The adhesiveshould be clear and have a preferable adherence to the protective sheet14 as opposed to the membrane 12. A water soluble adhesive is preferredso that if any remains on the membrane 12 after removing the protectivesheet it will wash away.

To apply the membrane 12 over a roof surface 30, two adjacent sheets 32and 34 of the roofing laminate 10 are laid down side by side over theroof surface 30. The membrane 12 of laminate 32 is fixed to the roof,generally using adhesives (not shown). However, other methods such asmechanically fastening the membrane to the roof can be employed. Secondsheet 34 of roofing laminate 10 is rolled out and adhered to the roofsurface adjacent the first sheet 32 with edge 36 of the second sheet 34overlapping edge 38 of the first sheet 32. The overlapping edges 36 and38 are adhered or welded to each other.

With the embodiment shown in FIG. 1, the edge portion 40 of theprotective sheet 14 on the first laminate 32 is pulled up enough toallow the edge 36 of the second membrane sheet to overlap the exposededge 38 of the first membrane 32. The two edges 36 and 38 are thenbonded together by heat or adhesive. As shown in FIG. 5, the edgeportion 40 of the protective sheet from the first laminate sheet 32 isthen folded back and rests over the overlapped portion 42 of the twomembranes 12,12.

As shown in FIG. 1, the protective sheet 14 covers the entire membrane12 from side to side. However, as shown in FIG. 8, the protective sheet14 may cover the entire membrane except for 4- to 12-inch portions oneither edges 26 and 28 of the laminate 10.

Alternately, as shown in FIG. 9, the protective sheet 14 can includeperforations 50,52 along side edges 26 and 28, which allow strips 54 and56 to be removed from the sheet leaving the field portion 56 of theprotective sheet protecting the membrane. Either of these embodimentsallow adjacent sheets of membrane to be bonded together while either thefield portion, as in FIG. 9, or the entire sheet, as in FIG. 8, remainon the membrane 12.

Once the roof is fully installed, all of the protective sheets arepulled away from the membrane leaving an exposed white or coloredmembrane surface free of scratches and dirt. In the event a protectivesheet or a portion of a protective sheet is inadvertently left on theroof, sunlight and water will cause it to disintegrate and wash away.

An alternate embodiment of the present invention is shown in FIG. 6wherein two protective sheets 20A and 20B protect the membrane 12.Sheets 20A and 20B overlap in the central portion of the membrane. Theoverlapped portion 58 lies loose on the membrane 12. The looseoverlapped portions 58 can be easily pulled up, allowing one to removeboth protective sheets 20A and 20B.

This has been a description of the present invention along with thepreferred method of practicing the present invention. However, theinvention itself should only be defined by the appended claims, WHEREINWE CLAIM:

What is claimed is:
 1. A roofing laminate comprising a roofing membraneand a protective sheet removably affixed directly to a first surface ofsaid membrane wherein said protective sheet is environmentallydegradable, and wherein said roofing membrane is formed from a polymerselected from the group consisting of EPDM, PVC and TPO and has athickness of 40-160 mils, and wherein said protective sheet is affixedto said first surface by a thin layer of water soluble adhesive.
 2. Theroofing laminate claimed in claim 1 wherein said membrane is white. 3.The roofing laminate claimed in claim 2 wherein said protective sheethas a color distinguishable from said white sheet.
 4. The roofinglaminate claimed in claim 1 wherein said adhesive adheres to saidprotective sheet when said protective sheet is separated from saidmembrane.
 5. The roofing laminate claimed in claim 1 wherein saidprotective sheet has a first sheet and a second sheet covering saidroofing membrane wherein said first sheet and second sheet areoverlapped along a central portion of said membrane.
 6. The roofinglaminate claimed in claim 1 wherein said protective sheet includes firstand second perforations along first and second edges of said protectivesheet.
 7. The roofing laminate claimed in claim 1 wherein saidprotective sheet does not cover first and second edge portions of saidroofing membrane.
 8. A roofing laminate comprising: a polymeric membranesheet selected from the group consisting of EPDM, PVC and TPO and havinga thickness of 40-160 mils and having an upper surface; and a protectivesheet adhered to said upper surface with an adhesive wherein saidprotective sheet is adhered to said upper surface by a thin layer ofwater soluble adhesive, wherein said adhesive adheres to said protectivesheet when said protective sheet is separated from said membrane.